In 67 patients with strictly anisometropic amblyopia, we found statistically significant correlations among three measurable parameters: the vision before treatment, the amount of anisometropia and the vision after treatment. The predetermined factors associated with success of treatment were 1) lower amounts of anisometropia, particularly less than six diopters for myopes, 2) better initial vision, and 3) a younger patient for hyperopic differences. Patients with less than three diopters of anisometropia were more likely to succeed with the use of glasses alone and a trial of glasses did not prolong therapy time. Despite a substantial number of older patients with extreme amounts of anisometropia or very poor vision, the group as a whole did well with 70% achieving 20/40 or better. Thus therapy should be approached enthusiastically, even for highly myopic patients since other authors have reported success with them. The factors under the control of the ophthalmologist which will promote success in these patients are correct glasses prescriptions, particularly with full astigmatic correction, continued use of glasses as maintenance therapy, and patience, since these children required a median of eight months for therapy to be successful.